Temperature control circuit, system and electrical equipment

Abstract

The utility model discloses a temperature control circuit, a temperature control system and electrical equipment, and belongs to the field of temperature control. The temperature-sensitive component is arranged on the surface of the load or inside the load, when the temperature of the load changes, the corresponding property of the temperature-sensitive component changes, and then the temperature measuring unit is connected with the temperature-sensitive component, so that the temperature measuring unit can detect the change of the property of the temperature-sensitive component, and then the actual temperature of the load is obtained. The temperature setting signal represents the set temperature, so that a first error comparison amplifying circuit in the current control unit can compare the set temperature with the actual temperature and then output the temperature to a PID circuit to obtain an adjusting signal, the adjusting signal can adjust the current of the temperature regulator after being input to a power amplifying circuit, and then the output of the temperature regulator is changed. The temperature of the load is maintained at a set temperature. According to the scheme, as long as the actual temperature of the load is different from the set temperature, rapid adjustment can be achieved, and the temperature stability of the load is guaranteed.

Description

Technical Field

[0001] This utility model relates to the field of temperature control, and in particular, to a temperature control circuit, system and electrical device. Background Technology

[0002] In some special cases, temperature control is very important. For example, the operating temperature of an LD semiconductor laser affects its output power and its output wavelength.

[0003] like Figure 1 The figure shows the relationship between the laser output power and the forward operating current of the LD at different temperatures. From the figure, we can see that:

[0004] 1. The threshold current Ith increases with increasing temperature, so the characteristic curve of the entire laser diode basically shifts in parallel with the temperature change.

[0005] If the LD operates at a constant current, its output power will change as the ambient temperature varies. Changing the temperature will result in different PI curves. When the injected current increases further, the PI curve shifts towards the I-axis, indicating increased carrier leakage and a decrease in the efficiency of carrier recombination into light radiation, leading to LD saturation.

[0006] The wavelength of a laser diode is primarily determined by the temperature of the semiconductor junction, the band gap of the material, and the current density. The semiconductor material determines the range of output wavelengths, which cannot be determined by the user. However, some research applications require a relatively wide wavelength range or a specific wavelength. Current technology has shown that a specific wavelength can be obtained by changing the die temperature. Therefore, if a very stable output wavelength is required, the die temperature and injection current must remain stable. For example, in a single-frequency laser system, the operating temperature of the LD needs to be maintained at 25°C.

[0007] Existing methods to ensure operating temperature all involve a constant temperature environment, but the load itself generates heat, and a constant temperature environment cannot be quickly adjusted. Utility Model Content

[0008] In order to overcome the shortcomings of the prior art, this utility model provides a temperature control circuit, system and electrical equipment to solve the problem that the existing technology ensures the working temperature in a constant temperature environment, but the load itself generates heat and the constant temperature environment cannot be quickly adjusted.

[0009] The technical solution adopted by this utility model to solve its technical problem is:

[0010] In a first aspect, a temperature control circuit is provided, comprising: a temperature regulator, a thermistor, a temperature measurement unit, and a current control unit;

[0011] The temperature regulator is located in the area where the load is located, and the temperature regulator is used to regulate the temperature of the area where the load is located.

[0012] The thermal component is disposed on the surface or inside the load;

[0013] The temperature measuring unit is connected to the thermistor and is used to measure the thermistor to obtain the actual temperature of the load.

[0014] The current control unit includes a first error comparison amplifier circuit, a PID circuit, and a power amplifier circuit.

[0015] The first input terminal of the first error comparison amplifier circuit is connected to the temperature measurement unit, and the second input terminal of the first error comparison amplifier circuit is connected to the temperature setting signal, which is the set temperature of the load. The output terminal of the first error comparison amplifier circuit is connected to the PID circuit, the PID circuit is connected to the power amplifier circuit, and the power amplifier circuit is connected to the temperature regulator to supply power to the temperature regulator.

[0016] Furthermore, it also includes: a current limiting unit, which is used to limit the current provided by the current control unit to the temperature regulator to be less than or equal to a set value;

[0017] The current limiting unit includes a current sampling circuit, a second error comparison and amplification circuit, and a protection circuit.

[0018] The current sampling circuit samples the current from the temperature regulator. The first input terminal of the second error comparison amplifier circuit is connected to the current sampling circuit, and the second input terminal of the second error comparison amplifier circuit is connected to a current limiting setting signal, which is the set value of the maximum current provided by the current control unit to the temperature regulator. The output terminal of the second error comparison amplifier circuit is connected to the power amplifier circuit through the protection circuit. When the sampled current is greater than the set value, the protection circuit activates to reduce the current flowing to the temperature regulator.

[0019] Furthermore, the current limiting setting signal is connected to the second input terminal of the second error comparison amplifier circuit through the first follower amplifier circuit.

[0020] Furthermore, the temperature setting signal is connected to the second input terminal of the first error comparison amplifier circuit via a second follower amplifier circuit.

[0021] Furthermore, the temperature measurement unit includes a temperature detection circuit and an error measurement circuit;

[0022] The temperature detection circuit is connected to the thermistor, the error measurement circuit is connected to the temperature detection circuit, and the temperature detection circuit is connected to the first input terminal of the first error comparison and amplification circuit.

[0023] Furthermore, the temperature detection circuit is connected to the first input terminal of the first error comparison amplifier circuit via a third follower amplifier circuit.

[0024] Furthermore, the temperature regulator is a TEC.

[0025] Furthermore, the thermistor is a thermistor.

[0026] Secondly, a temperature control system is provided, including: the temperature control circuit as described above.

[0027] Thirdly, an electrical device is provided, including: a temperature control system as described above.

[0028] The application employs the above technical solution and has at least the following beneficial effects:

[0029] This application provides a temperature control circuit, system, and electrical device. The temperature control circuit includes a temperature regulator, a thermistor, a temperature measurement unit, and a current control unit. The thermistor is disposed on the surface or inside the load. When the load temperature changes, the thermistor's properties change accordingly. The temperature measurement unit is connected to the thermistor, allowing it to detect the change in the thermistor's properties and thus obtain the actual load temperature. The temperature setting signal represents the set temperature. The first error comparison amplifier circuit in the current control unit compares the set temperature with the actual temperature and outputs it to the PID circuit to obtain an adjustment signal. This adjustment signal, input to the power amplifier circuit, adjusts the current of the temperature regulator, thereby changing the regulator's output and maintaining the load temperature at the set temperature. In other words, this application's solution can quickly adjust the load temperature whenever the actual load temperature differs from the set temperature, ensuring load temperature stability. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a graph showing the relationship between the output power and current of an LD at different temperatures, provided by an embodiment of this utility model.

[0032] Figure 2 This is a schematic diagram of a temperature control circuit structure provided in an embodiment of the present invention;

[0033] Figure 3 This is a schematic diagram of a specific temperature control circuit structure provided in an embodiment of the present invention;

[0034] Figure 4 This is a schematic diagram of a bridge measurement circuit provided in an embodiment of the present invention;

[0035] Figure 5 This is a schematic diagram of a constant current source measurement circuit provided in an embodiment of this utility model;

[0036] Figure 6 This is a schematic diagram of an error amplifier circuit provided in an embodiment of the present invention;

[0037] Figure 7 This is a schematic diagram of a PID circuit provided in an embodiment of the present invention;

[0038] Figure 8 This is a schematic diagram of a power amplifier circuit provided in an embodiment of the present invention;

[0039] Figure 9 This is a schematic diagram of a current limiting unit circuit provided in an embodiment of the present invention;

[0040] Figure 10 This is a schematic diagram of the voltage value of a temperature control test result provided by an embodiment of this utility model;

[0041] Figure 11 This is a schematic diagram of temperature values ​​for a temperature control test result provided by an embodiment of this utility model. Detailed Implementation

[0042] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this utility model will be described in detail below with reference to the accompanying drawings and embodiments. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. Based on the embodiments of this application, all other implementation methods obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0043] Reference Figure 2 This utility model provides a temperature control circuit, including: a temperature regulator, a thermistor, a temperature measurement unit, and a current control unit;

[0044] The temperature regulator is located in the area where the load is located, and the temperature regulator is used to regulate the temperature of the area where the load is located.

[0045] The thermal component is disposed on the surface or inside the load;

[0046] The temperature measuring unit is connected to the thermistor and is used to measure the thermistor to obtain the actual temperature of the load.

[0047] The current control unit includes a first error comparison amplifier circuit, a PID circuit, and a power amplifier circuit.

[0048] The first input terminal of the first error comparison amplifier circuit is connected to the temperature measurement unit, and the second input terminal of the first error comparison amplifier circuit is connected to the temperature setting signal, which is the set temperature of the load. The output terminal of the first error comparison amplifier circuit is connected to the PID circuit, the PID circuit is connected to the power amplifier circuit, and the power amplifier circuit is connected to the temperature regulator to supply power to the temperature regulator.

[0049] The temperature control circuit provided in this application includes a temperature regulator, a thermistor, a temperature measurement unit, and a current control unit. The thermistor is disposed on the surface or inside the load. When the load temperature changes, the properties of the thermistor change accordingly. The temperature measurement unit is connected to the thermistor, allowing it to detect the change in the thermistor's properties and thus obtain the actual load temperature. The temperature setting signal represents the set temperature. The first error comparison amplifier circuit in the current control unit compares the set temperature with the actual temperature and outputs it to the PID circuit to obtain an adjustment signal. This adjustment signal, input to the power amplifier circuit, adjusts the current of the temperature regulator, thereby changing the regulator's output and maintaining the load temperature at the set temperature. In other words, this solution allows for rapid adjustment whenever the actual load temperature differs from the set temperature, ensuring load temperature stability.

[0050] To more clearly illustrate the solution of this application, an embodiment of this application provides a specific temperature control circuit, such as... Figure 3 As shown: A temperature control circuit includes: a temperature regulator, a thermistor, a temperature measurement unit, and a current control unit;

[0051] The temperature regulator is located in the area where the load is located, and the temperature regulator is used to regulate the temperature of the area where the load is located; as a preferred implementation of this application, the temperature regulator is a TEC (thermal refrigeration device), and in other embodiments, the temperature regulator can be a device or circuit that can cool and / or heat.

[0052] The thermistor is disposed on the surface or inside the load; in a preferred embodiment of this application, the thermistor is a thermistor. In other embodiments, the thermistor may also be a thermistor device.

[0053] The temperature measuring unit is connected to the thermistor and is used to measure the thermistor to obtain the actual temperature of the load.

[0054] The temperature measurement unit includes a temperature detection circuit and an error measurement circuit;

[0055] The temperature detection circuit is connected to the thermistor, the error measurement circuit is connected to the temperature detection circuit, and the temperature detection circuit is connected to the first input terminal of the first error comparison and amplification circuit.

[0056] In one embodiment, the error measurement circuit is a bridge measurement circuit, taking a thermistor as an example, such as... Figure 4 As shown, R1, R3, R4, 10K thermistor R2, and reference voltage U Ref This forms a bridge measurement circuit, with the voltage U1 across the thermistor being:

[0057]

[0058] Setting voltage U2:

[0059]

[0060] Error signal ΔU=U1-U2 (1.1.3)

[0061]

[0062] When ΔU = 0,

[0063] R2×R3=R1×R4 (1.1.5)

[0064] That is, the conditions for bridge balance.

[0065] Differentiating both sides of equation (1.1.4) yields:

[0066]

[0067] When ΔU≠0, changes in URef will cause changes in ΔU; when the circuit reaches equilibrium, i.e., ΔU=0, U Ref Changes in the reference voltage will not affect ΔU. The advantage of this circuit is that when the circuit reaches equilibrium, changes in the reference voltage will not affect the stability of temperature control. The disadvantage is that the actual voltage and the resistance of the thermistor are not linearly related.

[0068] In another embodiment, the error measurement circuit is a constant current source measurement circuit, taking a thermistor as an example, such as... Figure 5 As shown,

[0069] A 100uA (1.2V / 12K) constant current source circuit is constructed using a 1.2V reference voltage (LM385), a 12K precision resistor (R44), and an operational amplifier (AR62A), as shown in the figure. The voltage U1 across the thermistor is thus calculated.

[0070] U1 = 100μA × R2 (1.1.7)

[0071] Where R2 is the resistance of the thermistor, which is not shown in the figure.

[0072] When the set voltage is U2, the error signal ΔU is:

[0073] ΔU=U1-U2 (1.1.8)

[0074] As can be seen from the above formula, since the set voltage U2 and the actual voltage U1 do not share a reference voltage, the stability requirements for the set voltage and the constant current source are high. The advantage of this circuit is that the relationship between the actual voltage and the thermistor resistance is linear, which facilitates the conversion from voltage to temperature.

[0075] The current control unit includes a first error comparison amplifier circuit, a PID circuit, and a power amplifier circuit.

[0076] The first input terminal of the first error comparison amplifier circuit is connected to the temperature measurement unit, and the second input terminal of the first error comparison amplifier circuit is connected to the temperature setting signal, which is the set temperature of the load. The output terminal of the first error comparison amplifier circuit is connected to the PID circuit, the PID circuit is connected to the power amplifier circuit, and the power amplifier circuit is connected to the temperature regulator to supply power to the temperature regulator.

[0077] In another embodiment, the temperature setting signal is connected to the second input terminal of the first error comparison amplifier circuit via a second follower amplifier circuit.

[0078] In another embodiment, the temperature detection circuit is connected to the first input terminal of the first error comparison amplifier circuit via a third follower amplifier circuit.

[0079] The first error comparison amplifier circuit is as follows: Figure 6 As shown: The set voltage value and the actual temperature and voltage value on the thermistor are amplified by the instrumentation operational amplifier AD620 to generate the error signal. The gain of AD620 is determined by equation 1.1.9, and we can adjust the gain of AD620 by adjusting R8.

[0080]

[0081] PID circuits are the foundation of temperature controllers. The error signals generated by the set voltage U2 and the measured voltage U1 after passing through the instrument's operational amplifier are then processed by parallel proportional, integral, and differential circuits. Their outputs are then added together by a final inverting amplifier at an appropriate ratio and sent to the output terminal to obtain a control signal driving a power amplifier circuit. For example, Figure 7 As shown.

[0082] The main functions of each part of a PID circuit are as follows:

[0083] Proportional element: It reflects the deviation signal e(t) of the control system in real time and proportionally. Once the deviation occurs, the controller immediately takes control action to reduce the deviation.

[0084] Integral stage: Primarily used to eliminate steady-state error and improve the system's accuracy. As long as an error exists in the system, the integral controller continuously accumulates it, and the output control quantity changes accordingly until the error reaches zero. A key characteristic of the integral circuit is that the error is zero when the circuit reaches a steady state.

[0085] Differential element: It can reflect the changing trend (rate of change) of the deviation signal and introduce an effective early correction signal into the system before the deviation signal value becomes too large, thereby accelerating the dynamic response of the system, reducing the settling time, and thus improving the dynamic performance of the system.

[0086] Note: When applying PID control, the proportional gain, integral time constant, and derivative time constant must be adjusted appropriately to ensure good performance of the entire control system.

[0087] For example, such as Figure 8 As shown, to achieve bidirectional current drive of the thermoelectric cooler, the power amplifier circuit uses an OCL circuit, as illustrated in the figure. When Vout>0, Q1 is turned on, and the current flows through the thermoelectric cooler in the forward direction. When Vout<0, Q2 is turned on, and the current flows through the thermoelectric cooler in the reverse direction. To measure the current flowing through the thermoelectric cooler, a high-power 0.1-ohm resistor is connected in series in the load for TEC current limiting sampling.

[0088] As a preferred implementation of this application, it further includes: a current limiting unit, which is used to limit the current provided by the current control unit to the temperature regulator to be less than or equal to a set value;

[0089] The current limiting unit includes a current sampling circuit, a second error comparison and amplification circuit, and a protection circuit; the second error comparison and amplification circuit has the same circuit structure as the first error comparison and amplification circuit. However, different circuits can be configured according to actual needs.

[0090] The current sampling circuit samples current from the temperature regulator. The first input terminal of the second error comparison and amplification circuit is connected to the current sampling circuit, and the second input terminal of the second error comparison and amplification circuit is connected to a current limiting setting signal, where the current limiting setting signal is the set value of the maximum current provided by the current control unit for the temperature regulator; the output terminal of the second error comparison and amplification circuit is connected to the power amplification circuit through the protection circuit. When the sampled current is greater than the set value, the protection circuit operates to reduce the current flowing to the temperature regulator.

[0091] Exemplarily, taking the temperature regulator as a TEC for example, as Figure 9 shown, when the current flowing through the TEC is from top to bottom, the current sampling circuit samples the voltage from a 0.1-ohm sampling resistor in series with the TEC (voltage is convenient for acquisition, so voltage is used here. Actually, current can also be sampled, and correspondingly, the set value is also a voltage value at this time). The voltage (Vb>0) after being amplified by X2A is divided by Vreg and then compared with the voltage Vr1 of X1A. When Vb>Vr1, the diode D5 conducts, forming a negative feedback loop, which reduces the flowing current I, thereby reducing Vb until Vb = Vr1. It can be seen that the maximum current flowing through the TEC is a fixed current value related to Vr1. As long as the value of Vr1 (i.e., the current limiting value) is set, the TEC can be protected from being damaged due to overcurrent. When Vb<Vr1, the diode D5 does not conduct, and this circuit does not affect the main circuit.

[0092] Similarly, when the current flowing through the TEC is from bottom to top (reverse), the voltage sampled from a 0.1-ohm sampling resistor in series with the TEC is amplified by X2A (Vc0), divided by Vreg, then compared with the voltage A of X1A and then the reversed Vr2 of X1B. When Vc<Vr2, the diode D6 conducts, forming a negative feedback loop, which reduces the flowing current I, thereby reducing Vc until Vc = Vr2. Thus, the maximum current flowing through the TEC is a fixed current value related to (Vr2 and Vr1). As long as the set current limiting value is set, the TEC can be protected from being damaged due to overcurrent.

[0093] When Vc>Vr2, the diode D6 does not conduct, and this circuit does not affect the main circuit. Among them, D5 and D6 are protection circuits.

[0094] In another embodiment, the current limiting setting signal is connected to the second input terminal of the second error comparison and amplification circuit through a first follower amplification circuit.

[0095] It should be noted that the thermoelectric characteristic is that when the temperature of the thermistor changes by 1 degree, the relative change in its resistance value is defined as the thermal temperature coefficient of the thermistor. The temperature coefficient of the thermistor is negative and related to the temperature value. The lower the temperature, the higher the temperature coefficient and the higher the sensitivity.

[0096] Based on the above analysis, the main advantages of thermistors are: high sensitivity, large temperature coefficient of resistance, and suitability for high-precision measurements. However, due to their nonlinearity, linear interpolation is required to improve display accuracy. The curve is segmented according to the required accuracy; the more segments, the higher the approximate accuracy of the linearization. After segmentation, several broken line segments are used to approximate the curve, and the coordinates of the inflection points are stored in a table. During measurement, it is necessary to first determine which broken line segment corresponds to the thermistor value of the measured temperature, and then perform linear interpolation based on the slope of that segment to calculate the measured temperature.

[0097] Taking four inflection points as an example, this illustrates the interpolation process using linear interpolation. The coordinates of the four inflection points are as follows:

[0098] x-axis: R1 R2 R3 R4; y-axis: T1 T2 T3 T4

[0099] First section: The equation of the broken line between points (R1, T1) and (R2, T2) is written as:

[0100]

[0101] Second paragraph: The equation of the broken line between points (R2, T2) and (R3, T3) is written as:

[0102]

[0103] The third segment: The equation of the broken line between points (R3, T3) and (R4, T4) is:

[0104]

[0105] The general formula for the expression of temperature can be expressed as:

[0106]

[0107] In Equation 3.3.6, k is the index of the inflection point.

[0108] The thermistor resistance value interpolation method can be implemented using a microcontroller system. The thermistor resistance values ​​corresponding to 0℃~80℃ are put into the array t2r

[81] . The voltage signal collected by the analog-to-digital converter AD7705 is converted into digital and the thermistor resistance value is calculated by looking up the table.

[0109] In the physical prototype developed in this application, the single-channel temperature controller exhibits a temperature stability better than 0.032℃ over 9 hours.

[0110] The following technical parameters of the single-channel temperature controller were measured at the same time:

[0111] ■ Temperature control range: 10℃~65℃

[0112] ■ Control method: bidirectional current control (-3A to 3A, i.e., TEC current limit is set to 3A).

[0113] The voltage and temperature values ​​of the test results are as follows: Figure 10 and Figure 11 As shown.

[0114] The specific temperature control circuit provided in this application has the advantages of high control accuracy, rapid adjustment, good real-time performance, and simple design. It is also highly adaptable to the controlled object and can be applied to small-scale temperature control applications. The temperature control circuit can not only meet the temperature control requirements of semiconductor laser tubes, but also those of optical crystals with high requirements for temperature stability.

[0115] Based on the same inventive concept, this application also provides a temperature control system, including: the temperature control circuit provided in the above embodiments.

[0116] The temperature control system provided in this application includes a temperature control circuit as described in the above embodiments. The temperature control circuit includes a temperature regulator, a thermistor, a temperature measurement unit, and a current control unit. The thermistor is disposed on the surface or inside the load. When the load temperature changes, the corresponding properties of the thermistor change. The temperature measurement unit is connected to the thermistor, allowing it to detect the change in the thermistor's properties and thus obtain the actual load temperature. A temperature setting signal represents the set temperature. The first error comparison amplification circuit in the current control unit compares the set temperature with the actual temperature and outputs it to the PID circuit to obtain an adjustment signal. This adjustment signal, input to the power amplification circuit, adjusts the current of the temperature regulator, thereby changing the regulator's output and maintaining the load temperature at the set temperature. In other words, this application's solution can quickly adjust the load temperature whenever the actual load temperature differs from the set temperature, ensuring load temperature stability.

[0117] Based on the same inventive concept, this application also provides an electrical device, including: a temperature control system as provided in the above embodiments.

[0118] The electrical equipment provided in this application includes a temperature control system as described in the above embodiments. The temperature control system includes a temperature control circuit, which comprises a temperature regulator, a thermistor, a temperature measurement unit, and a current control unit. The thermistor is disposed on the surface or inside the load. When the load temperature changes, the thermistor's properties change accordingly. The temperature measurement unit is connected to the thermistor, allowing it to detect the change in the thermistor's properties and thus obtain the actual load temperature. A temperature setting signal represents the set temperature. The first error comparison amplification circuit in the current control unit compares the set temperature with the actual temperature and outputs it to the PID circuit to obtain an adjustment signal. This adjustment signal, input to the power amplification circuit, adjusts the current of the temperature regulator, thereby changing the regulator's output and maintaining the load temperature at the set temperature. In other words, this application's solution can quickly adjust the load temperature whenever the actual load temperature differs from the set temperature, ensuring load temperature stability.

[0119] It is understood that the same or similar parts in the above embodiments can be referred to each other, and the contents not described in detail in some embodiments can be referred to the same or similar contents in other embodiments.

[0120] It should be noted that in the description of this application, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Furthermore, in the description of this application, unless otherwise stated, "a plurality of" means at least two.

[0121] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0122] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A temperature control circuit, characterized in that, include: Temperature regulator, thermistor, temperature measurement unit, and current control unit; The temperature regulator is located in the area where the load is located, and the temperature regulator is used to regulate the temperature of the area where the load is located. The thermal component is disposed on the surface or inside the load; The temperature measuring unit is connected to the thermistor and is used to measure the thermistor to obtain the actual temperature of the load. The current control unit includes a first error comparison amplifier circuit, a PID circuit, and a power amplifier circuit. The first input terminal of the first error comparison amplifier circuit is connected to the temperature measurement unit, and the second input terminal of the first error comparison amplifier circuit is connected to the temperature setting signal, which is the set temperature of the load. The output terminal of the first error comparison amplifier circuit is connected to the PID circuit, the PID circuit is connected to the power amplifier circuit, and the power amplifier circuit is connected to the temperature regulator to supply power to the temperature regulator.

2. The temperature control circuit according to claim 1, characterized in that, Also includes: A current limiting unit is used to limit the current supplied by the current control unit to the temperature regulator to be less than or equal to a set value. The current limiting unit includes a current sampling circuit, a second error comparison and amplification circuit, and a protection circuit. The current sampling circuit samples the current from the temperature regulator. The first input terminal of the second error comparison amplifier circuit is connected to the current sampling circuit, and the second input terminal of the second error comparison amplifier circuit is connected to a current limiting setting signal, which is the set value of the maximum current provided by the current control unit to the temperature regulator. The output terminal of the second error comparison amplifier circuit is connected to the power amplifier circuit through the protection circuit. When the sampled current is greater than the set value, the protection circuit will activate to reduce the current flowing to the temperature regulator.

3. The temperature control circuit according to claim 2, characterized in that: The current limiting setting signal is connected to the second input terminal of the second error comparison amplifier circuit through the first follower amplifier circuit.

4. The temperature control circuit according to claim 1, characterized in that: The temperature setting signal is connected to the second input terminal of the first error comparison amplifier circuit via a second follower amplifier circuit.

5. The temperature control circuit according to claim 1, characterized in that: The temperature measurement unit includes a temperature detection circuit and an error measurement circuit; The temperature detection circuit is connected to the thermistor, the error measurement circuit is connected to the temperature detection circuit, and the temperature detection circuit is connected to the first input terminal of the first error comparison and amplification circuit.

6. The temperature control circuit according to claim 5, characterized in that: The temperature detection circuit is connected to the first input terminal of the first error comparison amplifier circuit via a third follower amplifier circuit.

7. The temperature control circuit according to claim 1, characterized in that: The temperature regulator is a TEC.

8. The temperature control circuit according to claim 1, characterized in that: The thermal component is a thermistor.

9. A temperature control system, characterized in that, include: The temperature control circuit as described in any one of claims 1-8.

10. An electrical appliance, characterized in that, include: The temperature control system as described in claim 9.

Images